<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <script src="https://cdn.staticfile.org/jquery/1.10.2/jquery.min.js"></script>
</head>

<body>
<a href="#" id="to-weixin">
    <div class="btn">
        启动微信
    </div>
</a>

<script>
    $('#to-weixin').on('click', function () {
        window.location.href = 'weixin://';
    });
</script>
</body>
</html>